Alarm system



Nov. 11, 1941.

M. E. REAGAN arm. 2,262,650

a: ALARM sysml Filed Sept. 8, 19:58

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' WITNESSES: INVENTORS Maurice Kenyan and f/v/as Michel. BY

Patented Nov. 11, 1941 ALARM SYSTEM Maurice E. Reagan. Wilkinsbnrg, 2a.,andMathiag Michel, Wauwatosa. Wla, asslgnors to Westinghouse Electric &Manufacturing Company, East Pittsburgh, Pa a corporation of Penny]-vania Application September 8, 1938, Serial No. 228,932

5Clalms.

Our invention relates, generally, to alarm systems, and it hasparticular reference to a multiple point alarm system for use in powerstations and the like.

It may often be found desirable to provide a signal and alarm system forindicating at a central point in a power station not only the operationof, but also the instantaneous operating condition of, a number ofdevices. This is particularly so with alarm systems which are used inconnection with a number of protective devices, such as bearingtemperature relays, oil pressure indicators, etc., for safeguardingequipment in a power station or the like. Any or several of theprotective-devices may operate under certain circumstances, and they mayremain in the operated position, or may subuquently return to the normalor inoperated position, should the fault be removed. It is, therefore,desirable that a system used with such an installation should be capablenot only of operating an alarm device immediately upon the functioningof some protective device to warn an attendant, but it shouldfurthermore provide an indication of the instantaneous operatingcondition of each such device. Moreover, it may also be found desirableto use in connection with such an installation a single alarm device,and in such a manner that the alarm device may be located nearby theattendant, by whom it may be reset after it has operated, to render itresponsive to notify him of subsequent operations of others of theprotective devices, without first requiring him to reset such protectivedevices as may have already operated.

It is, therefore, generally, an object of our invention to provide asimple and eifective manner for indicating the operating condition of aplurality of separate devices.

More specifically, it is an object of our invention to provide an energyimpulse alarm system for indicating at a central location the successiveor simultaneous operation of a plurality of protective devices andgiving an alarm signal.

Another object of our invention is to provide for automaticallyindicating at a central point in a station the operation of, and theinstantaneous operating condition of, a plurality of protective deviceswhich may be located at various points about the station.

A further object of our invention is to provide a simple and effectivemanner for effecting energizations of a signal alarm from a plurality ofseparately located control devices without requiring resetting of anoperated device to render the alarm device responsive to subsequentoperations of the other control devices.

Other objects will. in part, be obvious, and

' will, in part, appear hereinafter.

In practicing our invention, a single signal alarm device may beenergized upon the operation of any of a plurality of protective deviceswhich may be located at various points about a station, through theclosure of normally open control contact members associated with any ofthe protective devices to connect a condenser to the control circuit ofthe alarm device and thereby release an impulse of electrical energytherethrough of suillcient value to operate an alarm relay. At the sametime, indicating means, such as a lamp or the like, may be connectedthrough the control contact members to a source of energy so as toprovide a visible indication while the control contact members remain inthe closed position, thus showing at a glance the instantaneousoperating condition of each protective device. Unidirectional currentmeans may be provided to prevent the discharge from any of thecondensers from being diverted through the already closed contactmembers associated with any other protective device, so that if thealarm device is reset after operation, the subsequent operation of anyother protective device to close its control contact members and connectthe condenser associated therewith for discharge through the controlcircuit of the alarm device will be effective to energize the alarmdevice.

For a more complete description of the nature and scope of ourinvention, reference may be had to the following detailed description,taken in connection with the accompanying drawing, in which the singlefigure represents diagrammatically a signal system embodying a preferredform of our invention.

Referring to the drawing, it will be seen that the reference numeral ildenotes generally an alarm system wherein a single alarm device or bellI! may be connected to a source of energy I, through the operation of analarm relay II.

In order to eflect the desired energization of the alarm relay I havingan operating winding 2| upon the operation of any of a plurality ofprotective devices, such as a bearing thermostat\/ relay or the like(not shown), having control contact members 26, which may be located atvarious points ll about a power station, a plurality of condensers llmay be provided, each disposed in series circuit relation with anindieating means such as the lamp II, and a current limiting controlresistor 22 for energization from common control buses 23 and 24. Thecircuit may be traced from one terminal of the condenser II, throughcontact members 2!, a unidirectional current device 30, the purpose ofwhich will be explained later, conductor 32, operating coil 2|,conductor 33, andbus 24, to the opposite terminal of the condenser II.

The normally open contact members Ila of'th'e alarm relay It close uponoperation of the relay toconnect the alarmbell IZtoasourceoi' energy,such as the battery II, and so give an indication to an attendant or theoperation of the particular protective device which is associated withthe control contacts 2|. At the same timealosure oi the normally opencontact members "D of the alarm relay may complete a holding circuit forthe relay from the bus 22, through a current limiting resistance 25,contact members lib, operating coil 2|, conductor 22, to bus 24. Thealarm bell will then continue to ring and warn the attendant oi theopera.- tion of the protective device associated with the contactmembers 20, until the alarm relay is deenergized by the attendantclosing the normally Open push button 26, which provides a shunt pathabout the operating coil 28. .Upon deenergization oi the alarm relay,the contact members Ila and [6b open, disconnecting the alarm device 12from the source and interrupting the holding circuit of the relay.

In order to prevent the alarm relay it from then being immediatelyreenergized should the control contacts 28 remain closed, by the flow ofcurrent through the path from the bus 23, through control resistor 22,indicating lamp 20, control contacts 26, unidirectional current devicel0, conductor 32, and operating coil 28, to bus 24, the control resistor22 may be so designed as to limit the current flow through theindicating lamp to a value sufficient to light the lamp, but below thatrequired for the operation of the alarm relay i8.

The unidirectional current devices 3|! are disposed in series circuitrelation between the control contact members 26 and the conductor 22 forpreventing the discharge from another of the condensers it upon it beingsubsequently connected to the alarm relay by closure of its associatedcontrol contact members 26, from being diverted through the controlcontact members 26 of a protective device which has previously operatedand which may have remained in the closed position. Thus the diversionof such discharge from the operating coil 28 is prevented and the alarmrelay may respond to the subsequent closure of any of a plurality of thecontrol contact members 28, regardless of the fact that the contactmembers 26 of others oi! the protective devices which had previouslyoperated may have remained in the closed position.

From the above description it may be seen that we have provided throughour invention a simple and effective manner for providing bothinstantaneous warning or the operation of, and continuous indication ofthe operating condition of, a plurality of protective devices throughthe use of a signal alarm device. The system herein disclosed by usreadily provides for the indication at a central point in a station ofthe ope ation condition of a plurality of protective devices, may besafely used with existing relatively high voltage control buses, andcontains no complicated and expensive control devices which might besubject to failure. thus making it e onomical to install and easy tomaintain. While we have preferred to illustrate this embodiment 01' ourinvention in connection with a plurality of protective devices, it maybe realized that our invention may also be readily and effectivelyutilized in any other suitable manner.

Since certain changes may be. made in the above construction anddiii'erent embodiments oi I the invention may be made without departingfrom the spirit thereof, it is intended that all the matter contained inthe above description, or shown in the accompanying drawing, shall beconsidered as illustrative, and not in a limiting sense.

We claim as our invention:

1. An alarm system comprising, alarm means, capacitor means normallycharged by a source of direct current, contact means operable to connectthe alarm means to the capacitor means to effect operation oi the alarmmeans therefrom, and indicating means effective upon operaation oi thecontact means to give visual indication 01 the operation of the contactmeans,

2. An alarm system comprising, indicating means, an alarm relay forcontrolling an alarm device. a condenser normally charged from a directcurrent source, and control means operable to contact said condenser tothe alarm relay to elect a single operation oi the alarm relay therefromand provide or energization of the indicating means.

3. An alarm system comprising, an alarm device, a relay for controllingthe energization of the alarm device, indicating means, a condenser,means connecting the condenser, and indicating means to a source ofdirect current in series circuit relation, control means operable i'oretlecting connection of the condenser in shunt circuit relation with therelay to provide a surge of electrical energy for eflecting a singleoperation of the said relay, circuit means for retaining the relay inthe operated position, and means for releasing the relay from theoperated position to render it responsive to subsequent surges ofelectrical energy, the impedance of said indicating means beingeiiective to limit the current through the relay while the control meansremain in the operated position to a value below that required foroperating the relay.

4. A multiple point alarm system comprising, a plurality of normallycharged capacitor devices connected to a source of direct current, aplurality of indicating means, alarm means, control means associatedwith each of said capacitor devices operable on predetermined conditionto connect the capacitor device to the alarm means to eflect anoperation of the latter, and unidirectional current means connected inseries circuit relation with each control means to prevent diversiontherethrough of a subsequent discharge 01' energy from any 01' saidcapacitor devices.

5. An alarm system comprising, an alarm device, a control relay operableto eilect the energization of the alarm device, a plurality ofcondensers connected for charging in shunt circuit relation with asource of direct current, an indicating means connected in seriescircuit relation with each condenser, control means operable to connecteach condenser in shunt circuit relation with the control relay foreflecting a single operation thereof to energize the alarm device andproviding an energizing circuit for said indicating means, and aunidirectional current device connected in series circuit relation witheach of said control means for preventing a subsequent discharge fromone of said condensers from being diverted from the control relay.

MAURICE E. REAGAN. MATHIAS mCHEL.

